在平面直角坐標(biāo)系中已知兩點(diǎn)A(cos80,sin80),B(cos20,sin20),則/向量AB/絕對(duì)值是多少?
熱心網(wǎng)友
A(cos80,sin80),B(cos20,sin20)則: |向量AB| = genhao[(cos80-cos20)^2 + (sin80-sin20)^2]= genhao(2 - 2cos80cos20 - 2sin80sin20)= genhao[2 - 2cos(80-20)]= 1
在平面直角坐標(biāo)系中已知兩點(diǎn)A(cos80,sin80),B(cos20,sin20),則/向量AB/絕對(duì)值是多少?
A(cos80,sin80),B(cos20,sin20)則: |向量AB| = genhao[(cos80-cos20)^2 + (sin80-sin20)^2]= genhao(2 - 2cos80cos20 - 2sin80sin20)= genhao[2 - 2cos(80-20)]= 1